PURPOSE: To prevent the occurrence of clogging of a nozzle or dust, by providing a meandering space in the middle of a channel from a gas introduction port in a hollow chamber to an opening of the main body of the nozzle, and by forming vacant chambers in front and the rear of said space.

CONSTITUTION: The main body 1 of a nozzle is provided in a vacuum treatment chamber 11 of a CVD apparatus, and a reaction gas is jetted, for instance, toward the surface of a silicon wafer 12 set in the treatment chamber and subjected to CVD treatment, from a slit-shaped opening 2 positioned in front of the wafer. When different kinds of gases are introduced into a hollow chamber 5 of the main body from a plurality of gas introduction ports located in the front, first the gases of different kinds are mixed in a vacant chamber 9 in front of a meandering space 8. Subsequently, the mixed gases are straightened when they pass through the meandering space 8, and then they are made uniform in pressure in a vacant chamber 10 in the rear and jetted from the opening 2. In the case of mixture of intensely-reactive gas species which may cause dust or pollution, they can be mixed only in a seal-shaped region in the vicinity of the surface of the wafer by making the nozzle multilayered.